6 binders cost $9.00. Which equation would help determine the cost of 11 binders?
There are several equations that could help determine the cost, each with a slightly different approach. We know the cost of 6 binders. We want to know the cost of 11 binders. We can write the numbers of binders as a proportion: $\dfrac{6}{11}$ We know 6 binders costs $9.00. We can let $x$ represent the unknown cost of 11 binders. The proportion of these costs can be expressed as: $\dfrac{\$9.00}{x}$ The cost changes along with the number of binders purchased, and so the two proportions are equivalent. $\dfrac{6}{11} = \dfrac{\$9.00}{x}$